Generation of Oxygen Vacancy and OH Radicals: A Comparative Study of Bi₂WO₆ and Bi₂WO6−x Nanoplates

A comparative study of visible‐light‐responsive Bi 2 WO 6 and oxygen‐deficient Bi 2 WO 6− x nanoplates was conducted. The formation of oxygen vacancy resulted in the band gap narrowing of oxygen‐deficient Bi 2 WO 6− x , through an elevation of both of the conduction and valence band positions. FTIR spectra revealed that much more surface hydroxyl groups have been detected after the etching process. The scavengers tests confirmed the generation of ⋅OH radicals during photochemical reaction for Bi 2 WO 6− x , whereas no . OH radicals can be detected for pure Bi 2 WO 6 . The photocatalytic activities of optimized Bi 2 WO 6− x on the decomposition of Rhodamine B (RhB) was three times as high as that of pure Bi 2 WO 6 . The improvement of photocatalytic activity on degradation of RhB and phenol can be ascribed to the synergistic effect of oxygen deficiency‐induced band shifts, together with the large quantities of surface hydroxyl groups providing active sites for the generation of OH radicals ( . OH).